1. Field of Invention
The present invention relates to a magnetization apparatus and, in particular, to a magnetization apparatus that can extend the lifetime of the energy storage element and reduce the energy loss to enhance the efficiency.
2. Related Art
The targeted therapy is to inject a targeted medicine into a patient body to attack a specific cell (e.g. a tumor cell). However, the injected targeted medicine may be dispersed to every part of the body, so the targeted therapy efficiency is decreased. Besides, the dispersion of the medicine may cause unpredictable side effect, which may bring additional injury to patients. In order to improve the efficiency of targeted therapy, the magnetic guidance control system is introduced to the targeted therapy. The magnetic guidance control system includes a magnetic field generating apparatus for generating a proper magnetic force, which can guide the magnetic targeted medicine to a specific area so as to effectively treat a certain disease.
FIG. 1 is a circuit diagram showing a conventional magnetization apparatus 1, which can control a magnetic field generating apparatus to generate the desired magnetic field for guiding the magnetic particles or magnetic medicine to a specific position so as to effectively treat a certain disease.
The magnetization apparatus 1 includes a DC voltage supply unit 11, an energy storage element 12, an energy release unit 13, three full-bridge conversion units 141-143, and a current feedback unit 15.
The DC voltage supply unit 11 generates at least one exciting signal ES for enabling the coils TA, TB and TC to generate magnetic fields to control the magnetic particles or magnetic medicine. The energy storage element 12 is electrically connected with the DC voltage supply unit 11 and stores the energy E generated by demagnetizing the coils TA, TB and TC. The energy release unit 13 is electrically connected with the DC voltage supply unit 11 and the energy storage element 12 for eliminating the energy E generated by demagnetizing the coils TA, TB and TC. The full-bridge conversion units 141-143 are electrically connected with the DC voltage supply unit 11, the energy storage element 12 and the energy release unit 13, and respectively connected to the coils TA, TB and TC. The full-bridge conversion units 141-143 are alternately turned on. That is, the coil of one phase is excited after another coil of a previous phase is demagnetized to eliminate the energy E. In addition, each of the full-bridge conversion units 141-143 includes four switches S1-S4. FIG. 1 only shows the switches S1-S4 of the full-bridge conversion unit 141 connecting to the coil TA. The current feedback unit 15 respectively senses the currents flowing through the coils TA, TB and TC, and then outputs a control signal DS to control the ON/OFF statuses of the switches S1-S4 of the full-bridge conversion units 141-143, thereby exciting or demagnetizing the coils TA, TB and TC, respectively. As a result, the magnetic particles or magnetic medicine can be controlled and guided to the specific position.
Taking the coils TA as an example, however, when the exciting signal ES is in a low voltage level, the control signal DS controls to turn on the switches S2 and S3 and turn off the switches S1 and S4 so as to eliminate the energy E generated by demagnetizing. In this case, the energy E generated by demagnetizing the coil TA can flow back to the energy storage element 12 and the energy release unit 13 through the switches S2 and S3, so that the terminal voltage of the energy storage element 12 increases and exceeds the rated voltage of the energy storage element 12. This usually shortens the lifetime of the energy storage element 12. In addition, the conventional energy release unit 13 does not have the passive demagnetizing function, so it must be synchronized with the DC voltage supply unit 11. In other words, after the exciting signal ES of one coil is switched to a low voltage level and the energy release unit 13 is simultaneously enabled to absorb the energy E generated by demagnetizing the coil, another coil can then be excited. For example, after the coil TA is demagnetized and the energy release unit 13 absorbs the energy E generated by demagnetizing the coil TA, the DC voltage supply unit 11 outputs another exciting signal ES to excite another coil TB. This configuration usually results some loss of the energy E at the energy release unit 13 and thus decreases the efficiency of the magnetization apparatus 1.
Therefore, it is an important subject of the present invention to provide a magnetization apparatus that can extend the lifetime of the energy storage element and reduce the energy loss to enhance the efficiency.